This is an introduction to drawing lines when given the slope and the y-intercept in an equation form. Remember that the y-intercept is where the graph crosses the y-axis; this is where we usually start. First, find the y-intercept, then determine the slope. For now, just focus on whether the slope is positive or negative.
Here are the variables we will start using in our function:
- m = slope
- b = y-intercept
The equation is y = mx + b. The x and y variables remain as letters, but m and b are replaced by numbers (ex: y = 2x + 4, slope = 2 and y-intercept = 4). The following video will show a few examples of understanding how to use the slope and intercept from an equation.
Video Source (03:53 mins) | Transcript
y = mx + b
This equation is called the slope-intercept form because the two numbers in the equation are the slope and the intercept. Remember, the slope (m) is the number being multiplied to x and the intercept (b) is the number being added or subtracted.
Additional Resources
- Khan Academy: Intro to Slope-Intercept Form (08:59 mins; Transcript)
- Khan Academy: Worked Examples: Slope-Intercept Intro (04:39 mins; Transcript)
Practice Problems
- Find the slope of the line:
\(\text{y}=6\text{x}+2\) - Find the y-intercept of the line:
\({\text{y}}=-7{\text{x}}+4\) - Find the slope of the line:
\({\text{y}}=-3{\text{x}}+5\) - Find the y-intercept of the line:
\({\text{y}}=-{\text{x}}-3\)
Solutions
- 6 (Written Solution)
- 4 (Written Solution)
- \(-3\) (Written Solution)
- \(-3\)
